Immunosuppressive biomaterial-based therapeutic vaccine to treat multiple sclerosis via re-establishing immune tolerance

Current therapies for autoimmune diseases, such as multiple sclerosis (MS), induce broad suppression of the immune system, potentially promoting opportunistic infections. Here, we report an immunosuppressive biomaterial-based therapeutic vaccine carrying self-antigen and tolerance-inducing inorganic nanoparticles to treat experimental autoimmune encephalomyelitis (EAE), a mouse model mimicking human MS. Immunization with self-antigen-loaded mesoporous nanoparticles generates Foxp3+ regulatory T-cells in spleen and systemic immune tolerance in EAE mice, reducing central nervous system-infiltrating antigen-presenting cells (APCs) and autoreactive CD4+ T-cells. Introducing reactive oxygen species (ROS)-scavenging cerium oxide nanoparticles (CeNP) to self-antigen-loaded nanovaccine additionally suppresses activation of APCs and enhances antigen-specific immune tolerance, inducing recovery in mice from complete paralysis at the late, chronic stage of EAE, which shows similarity to chronic human MS. This study clearly shows that the ROS-scavenging capability of catalytic inorganic nanoparticles could be utilized to enhance tolerogenic features in APCs, leading to antigen-specific immune tolerance, which could be exploited in treating MS.


Statistics
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Software and code
Policy information about availability of computer code Data collection Flow-cytometry data were acquired via MACSQuant VYB flow cytometer (Miltenyi Biotec, version No. 2.6.1515.13751) and were analyzed in FlowJo v10.0 software. Optical microscopy data were collected via (ECLIPSE Ti−U, Nikon, Japan. No custom code was used to collect data Data analysis Statistical analysis was performed by using GraphPad Prism v7. GraphPad Prism 7.00, Microsoft Excel 2013, and Microsoft PowerPoint 2013 for Windows were used to draw graphs and schemes For manuscripts utilizing custom algorithms or software that are central to the research but not yet described in published literature, software must be made available to editors and reviewers. We strongly encourage code deposition in a community repository (e.g. GitHub). See the Nature Portfolio guidelines for submitting code & software for further information.

Data
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March 2021
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Life sciences Behavioural & social sciences Ecological, evolutionary & environmental sciences
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Life sciences study design
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Flow Cytometry
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Methodology
Sample preparation For spleen samples, they were processed through mechanical disruption and filtered through 70-μm cell strainer. Cells were then centrifuged for 5 min, 2000 rpm, 4 °C lysed by ammonium-chloride-potassium (ACK) lysing buffer (Lonza), then the collected cells were washed twice by cold PBS Spinal cords were dissociated in cold PBS containing 1 mg/mL collagenase type IV and 20% EDTA/trypsin and incubated at 37 °C for 20 min. RPMI 1640 containing 10% fetal bovine serum was added to each sample to inhibit enzymatic activity, and the cells were filtered through a 40-μm cell strainer. The cells were collected by centrifugation according standard protocol The isolated cells were first stained with FcR blocking reagent, followed by antibodies against surface antigens. For transcription factor staining, cells were subsequently fixed, permeabilized by Foxp3/Transcription Factor staining buffer set (eBioscience) and stained with antibody against Foxp3. All antibodies were diluted according to manufacturer's recommendations Instrument Stained cells were analyzed by a MACSQuant VYB flow cytometer (Miltenyi Biotec) Software Treestar FlowJo v10.0 was used to gate the samples and Graphpad was used for statistical analysis Cell population abundance At least 60,000 total events were acquired for in vitro FACS analysis of BMDC activation and ROS scavenging experiments. At least 300,000 total events were acquired for FACS analysis in vivo Gating strategy All cells were gated based on forward-scatter and side-scatter characteristics to exclude dead cells and debris. Singlet cells were gated using FSC-H and FSC-A. Subsequently, cells were gated based on isotype controls, and the frequencies of positively stained cells for each marker was recorded Tick this box to confirm that a figure exemplifying the gating strategy is provided in the Supplementary Information.